Touch panels are provided with sensors, which detect the position where the touch panel surface is pressed by an object (e.g., a finger). Each of such sensors includes first electrodes and second electrodes, which extend perpendicularly to each other. As is well known in the art, an insulating layer is interposed between the first electrodes and the second electrodes.
The first electrodes and the second electrodes comprise a mesh made up of intersecting fine lines of metal. Spaces, which are surrounded by the intersecting fine lines of metal, also are referred to as cells. Recently, attempts have been made in display devices including touch panels to incorporate an irregularly shaped mesh of electrodes in order to prevent generation of moire phenomena (interference fringes) due to the geometrical relationship between the electrodes and the pixels that make up the display screen. In other words, the shapes of the cells are irregular (non-uniform), i.e., are of a random pattern (see Japanese Laid-Open Patent Publication No. 2011-517355 (PCT)). The fine lines of metal mostly comprise fine lines of silver (Ag) in view of electroconductivity, cost, color, etc., which are taken into account.
As disclosed in Japanese Laid-Open Patent Publication No. 2011-074308, a first electrode layer, which includes the first electrodes arranged in the foregoing manner, or a second electrode layer, which includes the second electrodes arranged in the foregoing manner, is applied to a display device, a board, an optical sheet, or the like by an optically clear adhesive (OCA). Since the first electrode layer or the second electrode layer is convexly shaped toward the insulating layer, which serves as a base, steps are formed between the insulating layer and the first electrode layer or the second electrode layer. The OCA is required to cover both the insulating layer and the first electrode layer or the second electrode layer adequately regardless of such steps (better step conformability).